APES Health Toxins General Notes - Shope

HEALTH TOXINS




• morbidity
o causing disease


• mortality
o causing death (death rates)


• toxins
o poisons/chemicals that have adverse health effects


• toxicology
o the study of poisons


• toxicity
o the measure of how harmful a poison is


• note: all chemicals can be considered toxins at some level


• classes of toxins
o A – asphyxiants – toxins that interfere with breathing
o B – allergens – toxins that cause a physical reaction as an immune response
o C – neurotoxins – damage or paralyze nerves
o D – irritants – inflame skin or epithelial tissue
o e – mutagens – toxins causing damage to DNA
o f – teratagens – toxins causing birth defects
o g – carcinogens – cancer causing


• LD50
o a measure of toxicity
o the amount of a chemical that will cause death in 50% of the a population
o usually measured in milligrams of toxins per kilogram of body weight
o ex.: give toxin to lab rat… this it the point at which 50% of them die


• ED50
o the amount needed to have a certain effect on 50% of the population
o effect can be good (cure) or bad (headaches, nausea)


• dose – response
o linear – slope depending on severity
o threshold – tolerance until a certain point… most substances have this

• bioaccumulation
o an increase in the concentration of a chemical over time
o it occurs when a chemical is taken in faster than it can be eliminated
o usually occurs with fat soluble chemicals

• biomagnification
o chemical becomes more concentrated as it moves up food chain
o ex.: the concentration of DDT in the fatty tissues of organisms in a food chain (studied by Rachel Carson)

• Thalidomide
o 1960s
o popular in Europe
o came to US… approved by FDA
o given to pregnant women to fight nausea
o causes birth defects in children: teratagen
o was banned but is now being used (carefully) to treat some adult neurological disorders (?)